<HTML><HEAD><TITLE>recorded(+Key, ?Value, -DBRef)</TITLE>
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<H1>recorded(+Key, ?Value, -DBRef)</H1>
Succeeds if the term Value has been recorded in the indexed database under
the key Key and DBRef is its unique reference.


<DL>
<DT><EM>Key</EM></DT>
<DD>An atom or a compound term.
</DD>
<DT><EM>Value</EM></DT>
<DD>Any Prolog term.
</DD>
<DT><EM>DBRef</EM></DT>
<DD>A variable.
</DD>
</DL>
<H2>Description</H2>
   Used to find all values associated with a key.  Value is unified with
   the first term that is associated with Key.  DBRef is unified with the
   unique database reference of this database entry.  In the case of
   compound terms, all keys of the same name and arity are treated as
   equal. If Value is instantiated, the instantiated term is used as a
   filter to reduce the number of terms returned by the recorded database
   and unified with Value, thus improving the speed of retrieving the term.


<P>
   Backtracking will unify Value and DBRef with the value resp.  the
   database reference of successive values associated with Key in the order
   in which they were recorded.

<P>

<H3>Modes and Determinism</H3><UL>
<LI>recorded(+, -, -) is nondet
<LI>recorded(+, +, -) is nondet
</UL>
<H3>Modules</H3>
This predicate is sensitive to its module context (tool predicate, see @/2).
<H3>Fail Conditions</H3>
Fails if nothing is recorded under the key Key
<H3>Exceptions</H3>
<DL>
<DT><EM>(4) instantiation fault </EM>
<DD>Key is not instantiated.
<DT><EM>(5) type error </EM>
<DD>Key is neither an atom nor a compound term.
<DT><EM>(5) type error </EM>
<DD>DBRef is neither a variable nor a database reference.
</DL>
<H2>Examples</H2>
<PRE>
   Success:
   [eclipse]: recordz(beer, paulaner, _),
   recordz(beer, lowenbrau, _),
   recorded(beer, Value, Ref).
   Value = paulaner
   Ref = 'DBREF'(16'50470e90)     More? (;)
   Value = lowenbrau
   Ref = 'DBREF'(16'50470ea8)     More? (;)
   no (more) solution.
   Fail:
   erase_all(beer),recorded(beer,guiness, Ref).
   Error:
   recorded(Beer,Value,Ref).            (Error 4)
   recorded("beer",Value,Ref).          (Error 5)
   recorded(1,Value,Ref).               (Error 5)


</PRE>
<H2>See Also</H2>
<A HREF="../../kernel/record/recorda-3.html">recorda / 3</A>, <A HREF="../../kernel/record/recordz-3.html">recordz / 3</A>, <A HREF="../../kernel/record/erase-1.html">erase / 1</A>, <A HREF="../../kernel/typetest/is_handle-1.html">is_handle / 1</A>, <A HREF="../../kernel/record/referenced_record-2.html">referenced_record / 2</A>
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